1. Technical Field of the Invention
This invention relates generally as indicated to clamps for circular objects, and to such clamps are parts of seismic sway braces.
2. Description of the Related Art
Clamps for holding circular objects such as pipes or conduit are commonly used in a wide variety of circumstances, such as to secure the objects to structure, to secure other objects or fixtures to the circular objects, or to otherwise limit movement of the circular objects.
One example of a clamp used for holding circular objects is a riser clamp, used to secure vertical pipe runs, such as in a plumbing stack. A stack is a vertical run of pipe through a building, used for example to vent plumbing drain lines. The vertical run may be several stories high, passing through circular floor openings that are greater in diameter than the diameter of the pipe run.
These vertical runs of pipe are secured by riser clamps. An example prior art riser clamp 1 is shown in FIG. 1. The riser clamp 1 has a pair of bar portions 2 of rectangular cross-section bar each having a pair of straight ends 3 with a circular portion 4 between the straight ends 3. The bar portions 2 are clamped onto a pipe or conduit 5, with opposite sides of the pipe 5 engaged by surfaces of the circular portions 4. The bar portions 2 are secured onto the pipe 5 by a pair of bolts 6 that pass through holes 7 in the straight ends 3 on either side of the circular portions 4, and nuts 8 that threadedly engage the bolts 6. The nuts 8 are tightened to clamp the pipe 5 securely between the circular portions 4. The circular portions 4 are configured so that the straight ends 3 of the portions 2 do not come into contact when the riser clamp 1 is installed, but rather there is a spacing between the straight ends 3 of one of the bar portions and the corresponding straight ends 3 of the other bar portion.
A riser clamp such as the riser claim 1 is secured to a vertical run of piping just above a circular floor opening though which the pipe run passes. The riser clamp 1 ordinarily rests on the floor, with the straight ends 3 being long enough to extend beyond the circular floor opening. Thus one function of the riser clamp 1 is to prevent vertical movement of the pipe, since the riser clamp 1 is too large to fit through the circular floor opening.
In addition, the riser clamp 1 prevents torquing or tilting of the pipe run. The spacing between the corresponding straight ends 3 of the portions 2 provides a stable base that resists twisting or torquing of the pipe that would otherwise result in tipping of the clamp 1 over an edge of the straight ends 3 of one of the portions 2. In other words, having the corresponding straight ends 3 of the portions 2 separated from each other provides a base that engages the floor around the circular floor opening to prevent undesirable twisting, tilting, and/or torquing of the pipe run.
Nonetheless, there is room for improvement in that the riser clamp 1 involves a large number (six) of separate parts, and two different threading operations. In addition, some care must be taken to provide at least rough symmetry between the tightening of the nuts 7 on opposite sides of the pipe 5, to have proper installation of the riser clamp 1.
From the foregoing it will be appreciated that improvements would be desirable for pipe or conduit clamps in general, and for riser clamps in particular.
One motivation for securing objects such as pipes is to prevent damage during seismic events such as earthquakes. Seismic sway bracing is often required for plumbing systems, fire sprinklers, electrical systems, heating conduits, ventilation conduits, air conditioning conduits, and other structural and non-structural components of a building as well as some equipment installed in buildings. Previously installation of pipe clamps and seismic sway bracing involved disassembling the service pipe clamp and then the reassembling around the service pipe. This is time consuming and also provides the opportunity to lose nuts and bolts in the installation process. Frequently installation is high in the air working near a ceiling so the dropping of nuts and bolts during installation wastes significant time which costs more money during installation. From this it will be appreciated that improvements would be desirable in bracing for pipes and conduits.